Drifting-valve.



s. w. BUC'KLAND @L H. McvlcAR. DRIFTING VALVE. APPLICATION FILED OCT.I5, I9I1.

l ,284,952 Patented Nov. 12, 1918.

FxgI.

@E ll'l@ FTE FFQE JOSEPH WELLINGTON BUCKLAND AND ROBERT MCVICAR, OFMONTREAL, QUEBEC, CANADA.

DRIFTING-VALVE.

Specification of Letters Patent.

Patenten Nov. i2, 191s.

Application iled October 15, 1917. Serial No. 196,747.

To all whom it may concern.'

Be it known that we, JOSEPH VELLINGTON BUCKLAND and ROBERT MCVICAR, bothofthe city of Montreal, Province of Quebec, Dominion of Canada. bothsubiects of the King of Great Britain, have invented certain new anduseful Improvements in Drifting- Valves; and we do hereby declare thatthe following is a full, clear, and exact description thereof.

In order to obviate any tendency for a vacuum to be created in thecylinders and steam chests of locomotives when drifting, the practice isto employ an automatically controlled auxiliary steam supply theessential operating element of which is usually an automaticdifferential Valve. This valve stays open when the engine is travelingat a. high speed, fifty strokes per minute or more for instance, andopens and closesintermittently when the engine is making. less thanfifty strokes per minute.

rl`he effect which causes the valve to remain open is the exhaustinginfluencesex'- ertedA upon the upper side of the valve synchronouslywith'the engine strokes, and with the exhaust acting with this frequencyof fifty per minute the intervals of time between them are not ofsuflicient duration to permit the valve to close. Consequently althoughthe valve may flutter in its full open position it will neverappreciably diminish the flow of the auxiliary steam to the steam chestswhile it is needed to relieve a drifting engine having this relativelyhigh speed. l/Vhen the frequency of the exhaust drops however, owing tothe slowing down of the locomotive, the intervals between the exhaustsare of suiicient duration to permit the valve to close; and each time itcloses there is a protraction beyond the actual interval between thestrokes of the piston due to the fact that the pressure in the cylindermust be reduced to a degree lower than atmospheric before the valveopens. |The object of the present invention is to increase the frequencyof the exhausts exerted in the differential valve chamber, and therebycause the valve to remain open practically until the engine is stopped.The result obtained is a substantially continuous supply of auxiliarysteam during the movement of the engine at a very low speed.

The best practical results are obtained by our invention when theautomatic differential valve above-mentioned is employed, the

peculiar construction of the differential valve proper and thecontiguous portion of the valve casing wherein the steam admission portis contained forming a nozzle and causing the inflowing steam to createa suction thereon and immediately in advance of the said nozzle whichsuction is transmitted through the nozzle and an axial port in the valveto the upper side thereof. The inflowing steam is caused to imw'rfre onthe underside of the valve before exerting a suction influence on thenozzle. T he effect is that an exhausting influence is caused on thegreater differential face of the valve and simultaneously the impact ofthe auxiliary steam assists the exhausting influence in tending to keepthe differential valve open even during the movement of the engine at avery low speed.

The invention may be said to consist of a unitary drifting valveincluding means whereby the valve proper when automatically opened willhave a tendency to remain open owing to a peculiar construction andarrangement of the parts whereby the auxiliary steam from a unitaryvalvular means reaches a plurality of steam chests and through themrelieves the disturbance in a plurality of cylinders due to thelocomotive drifting` or. in other words running with the throttleclosed.

For full comprehension. however, of my invention reference must be hadto the accompanying drawings forming a part of this specification inwhich similar reference characters indicate the same parts, and whereinFigure l is a fragmentary front elevation of an engine frame with ourinvention applied thereto;

Fig. 2 is a side elevation partly in vertical axial sectional view takenon line 2-2 Fig. 3; and

Fig. 3 is a similar sectional view taken on line 83 Fig. 2.

The casing of our improved distribution valve is formed with an uppercylindrical portion b and a bottom branched portion c presentingoppositely extending ends tapped to serve as pip-e connections; aportion of this casing midway its height being of straight cylindricalform to constitute a valve seat l into which a vane c cast integrallytherewith upwardly projects. This vane is of sufliciently less diameterthan the seat to present a surrounding annular chamber f and slightlyabove the bottom of this chamber it is surrounded by an annular port gwith which is connected at L a pipe leading from the boiler. lThiscasing is closed by a cap Z.

The automatic valve operating within this chamber is of the diferentialtype and preferably of inverted conodial form, the apex of which istruncated and in the form of a nozzle which is surrounded by acylindrical valve forming an integral part thereof the .lower end m ofwhich is of annular form and disposed with its bottom edge 1n line withthe truncated apex of the nozzle n, the annular member m being connectedto the nozzle by a web m which is an integral part of the nozzle andvalve and constitutes with the edge of m and the apex of the nozzle theminor face of the differential valve proper. rl`his face has an annularconcavity 50 yencircling the nozzle and with which the annular vane ecoincides. The inverted base p of the valve is of piston form andadapted to-reciprocate in the cylindrical portion b of the casing. lThispiston and valve 7c are provided with packing rings g. The lower end ofthe casing between the nozzle and valve and the bottom of the casingbetween the pipe connection branches is expanded as at r. This automaticvalve is chambered and provided with an axial port y'.

Our improved valve is located between the steam chests as shown at b inFig. 1 and a pair of steam pipes 'w connect the pipeconnection branchesc to the steam chests and thence to the cylinders indicated at m at theopposite sides of the engine.

ln order to provide a drain for the valve and at the same time thenecessary atmospheric pressure communication, a drip pipe u connects anopening v in the valve casing p below its cylindrical seat d and extendsdownwardly between the engine frames and to within a short distance ofthe rail level.

0 pera tion.

In th-e operation of our invention, the engine being in motion, when thethrottle is closed and the steam pressure in the main valve chamber andcylinder drops below atmospheric pressure, the diiferential valve islifted thus uncovering the steam port g and admitting auxiliary steamdirect to the two steam chests simultaneously through pipes zo, w.

c This flow of the steam from port g, the valve being at the top of itstravel.y lirst meets the vane e which deflects it upwardly against thetop of the concavity 50 in the valve between the Hange m and the nozzlen andthe impacthas a lifting effect. The steam is then dciiecteddownwardly and follows the surface of the nozzle and is concenn tratcdin a solid jet at a point immediately beneath and in close proximity tothe truncated apex of the nozzle and flows directly into the pipes w,the expanded port z' affording ample clearance to prevent anaccumulation of pressure at the apex of the nozzle and thereby avoid aback pressure of steam through port y' to the top and larger area of thevalve. The effect is that a suction is exerted on the port y' andconsequently on the upper side of the valve while steam is flowing andthis tendency to create a vacuum assists in maintaining the latter inits lifted and open position. This advantageous result is due to theaction of the steam by reason of the baiiler-vane e, concavity 50,nozzle, port j, expanded port r and the fact of the two steam pipes wleading to the two steam chests, being served.

An important feature of this beneficial result is that the automaticvalve works more smoothly at slow speed by reason of the division of thetime of the exhausts. Our invention gives communication between bothsteam chests and consequently four centers of disturbance, and as eachdisturbance in the cylinder causes a movement of the difterential valve.and each revolution of the wheel of the engine causes four disturbances,by our invention connecting a single valve with a plurality of steamchests the exhausts exerted on the differential valve proportionatelymeasured in frequency, results` in smoothness.

Another advantage of the plurality of connections between thedifferential valve chamber and the plurality of steam chests is that anopen communication of full capacity constantly exists between the mainvalve chambers. The effect is that we practically prevent backing-up ofthe auxiliary steam in this main valve between the ports, thisbacking-up being due to the retardation of the flow of the auxiliarysteam because of the slow movement of the piston in the main cylinder,which has the'disadvantageous effect of a backing-up pressure in thedifferential valve chamber thereby causing a tendency of thedifferential valve to close when it should be open. 'By our connectionof the differential valve to two or more steam chests this tendency toretard the flow of the auxiliary steam is reduced to a minimum.

lVhat we claim is as follows 1. The combination with a unitary driftingvalve for the relief of locomotive cylinders, the casing thereof havingan inlet for drifting steam and such casing containing an automaticdifferential valve proper having a downwardly projecting nozzle and aconcentric valvular member constitutingthe lower end of the valve andformed with a concavity therein. the upper end of the valve being ofgreater arca than the lower end and of piston form, and means effectinga constantly open communication between the upper and lower sides of thevalve, of a connection forming an intimate component part of the valvecasing and having an annular baliler-vane accommodated within theannular concavity of the valve when the latter is closed and a twin pipeconnection for communication with the cylinders at the Opposite sides ofthe locomotive.

2. The combination with a unitary drifting valve for the relief oflocomotive cylinders, the casing thereof having an inlet for driftingsteam and such casing containing an automatic dil'erential valve properhaving a downwardly projecting central nozzle and a concentric valvularmember constituting the lower end of the valve and formed with anannular concavity therein, the upper end of the valve being of greaterarea than the lower end and of piston form, such valve having an axialport therethrough and the casing having an Opening to the atmospherebelow the said upper end of the valve, of a connection forming anintimate component part of the valve casing and having an annularbafller vane accommodated within the annular concavity of the valve whenthe latter is closed and a twin pipe connection for communication withthe cylinders at the opposite sides of the locomotive.

In testimony whereof we have signed our names to this speccation in thepresence of two witnesses.

JOSEPH WELLINGTON BUOKLAND. ROBERT MGVIOAR.

Witnesses:

GORDON G. COOKE, WILLIAM J. C. HEWETSON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

